Image stabilization apparatus

ABSTRACT

An image stabilization apparatus comprises a housing accommodating an optical system in the interior thereof. A part of optical members that compose the optical system is held to allow angular displacement relative to the housing, and the position of the part of the optical members is maintained in a predetermined state. The part of the optical members is driven to restore the position angularly displaced. A driving amount is controlled based on information of the angular displacement. A mode for controlling the housing that is suitable for vibration applied to the housing is determined, and the mode is informed to a user.

[0001] This application claims the benefit of Japanese Patentapplication No. 2002-173031 which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an image stabilization apparatusto be equipped in various optical apparatus such as a binocular ormonocular.

[0004] 2. Related Background Art

[0005] Reference is made here, by way of example, to Japanese PatentApplication Laid-Open No. 10-104681, which discloses an imagestabilization apparatus. A prior art image stabilization apparatusdisclosed in this Japanese Patent Application Laid-Open No. 10-104681 isprovided with an erecting prism, a gimbaled member to which the erectingprism is attached, position feedback control means and angular velocityfeedback control means for controlling the position or posture of thegimbaled member. The angular velocity feedback control means is afeedback loop that detects an angular velocity of the gimbaled memberthat is created due to hand shake or other causes and enhancesfollowing-up ability of the gimbaled member to the optical axis of theobjective lens based on a detection result. A position feedback loop isa feedback loop that detects an angular displacement of the gimbaledmember that is created due to hand shake or other causes and enhancesfollowing-up ability of the gimbaled member to the optical axis of theobjective lens based on a detection result. With the above-describedstructure, Japanese Patent Application Laid-open No. 10-104681 teaches atechnology to change a gain of the position feedback control means inresponse to a user's switching operation of a mode switch to realize amode for reducing vibration created by hand shake and a mode forproviding a high following-up performance to panning and tiltingoperations.

[0006] Another patent document Japanese Patent Application Laid-Open No.2001-100106 discloses an image stabilization apparatus in which avibration reduction mode and a panning/tilting mode are switchedautomatically.

[0007] Specifically, in this prior art, the apparatus detects theangular velocity and an angular displacement of a gimbaled member anddetermines whether or not the detected values are larger (oralternatively, smaller) than predetermined values. Then, the apparatusdetermines an appropriate mode to automatically set this appropriatemode.

[0008] In addition, in the technology disclosed in Japanese PatentApplication Laid-Open No. 2001-100106, a user can freely switch the modeat his or her will by a manual operation. Even during observation undera mode that has been set manually, the apparatus detects the angularvelocity and the angular positional displacement of the gimbaled member,determines the appropriate mode, and when it is determined that theappropriate mode is different from the manually selected mode, the modeis automatically switched to the appropriate mode determined by theapparatus.

[0009] In the above-described technology disclosed in Japanese PatentApplication Laid-Open No. 10-104681, the mode is manually selected onuser's own discretion, and therefore it would be difficult for anunskilled user to determine the optimum mode definitely. Therefore, insome cases, a mode other than that selected by the user may be theoptimum mode. In such cases, the performance of the apparatus would notbrought out fully.

[0010] On the other hand, in the technology disclosed in Japanese PatentApplication Laid-Open No. 2001-100106, the switching of the vibrationreduction mode is effected automatically in accordance with the degreeof the vibration of the apparatus. However, if the mode is thus switchedautomatically, the mode determined by the apparatus as the appropriatemode sometimes differs from the mode that the user has selected inaccordance with his or her intention. In that case, the user sometimesfeels it undesirable to observe under the mode automatically switchedbased on the determination by the apparatus.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide an imagestabilization apparatus that has a good usability.

[0012] In order to attain the above object, according to one aspect ofthe present invention, there is provided an image stabilizationapparatus comprising:

[0013] a housing accommodating an optical system in the interiorthereof;

[0014] holding means for holding a part of optical members that composethe optical system in such a way as to allow angular displacement ofsaid part of the optical members relative to the housing, in order tomaintain the position of said part of the optical members in apredetermined state;

[0015] driving means for angularly displacing said part of the opticalmembers in the direction for restoring the position of said part of theoptical members that have been angularly displaced by the holdingmember;

[0016] control means for controlling a driving amount of the drivingmeans, the control means including detection means for detectinginformation on angular displacement of said part of the optical memberscaused by the holding means and determination means for determining,based on the information detected by the detection means, a mode forcontrolling the housing that is suitable for vibration applied to thehousing; and

[0017] an informing section that informs a user of the control methoddetermined by the determination means.

[0018] In the image stabilization apparatus according to the presentinvention, the angular displacement information may comprise informationon angular velocity of the holding means and/or information on angulardisplacement amount of the holding means.

[0019] In the image stabilization apparatus according to the presentinvention, the determination by the determination means may be madebased on a comparison of a predetermined reference value and the angulardisplacement information.

[0020] In the image stabilization apparatus according to the presentinvention, the reference value may comprise a reference value for theangular velocity and/or a reference value for the angular displacementamount.

[0021] In the image stabilization apparatus according to the presentinvention, the determination by the determination means may be madebased on a comparison of the reference value and the angulardisplacement information obtained within a predetermined sampling time,and based on the number of times the angular displacement informationbecomes larger than and/or smaller than the reference value.

[0022] In the image stabilization apparatus according to the presentinvention, the control mode determined by the determination means may beselected for at least two vibration reduction modes.

[0023] In the image stabilization apparatus according to the presentinvention, the apparatus may be so adapted that the user can select anautomatic switching mode in which the control mode is automaticallyswitched to the mode determined by the determination means based on theangular displacement information detected by the detection means or auser setting mode in which the user is allowed to select the controlmode.

[0024] In addition, in this image stabilization apparatus, when theselected mode is the user setting mode, the informing section may beadapted to provide information on whether the mode selected under theuser setting mode and the mode determined by the determination means aredifferent or identical.

[0025] In the image stabilization apparatus according to the presentinvention, the informing section may be adapted to provide informationon the control mode determined by the determination means.

[0026] In the image stabilization apparatus according to the presentinvention, the apparatus may be so adapted that the user can select andset any mode based on the control mode of which the user is informed bythe informing section.

[0027] The image stabilization apparatus according to the presentinvention may further comprises first calculation means for performingcalculation on a detection result of the detection means based on afirst predetermined calculation method to determine the driving amount,second calculation means for performing calculation on a detectionresult of the detection means based on a second predeterminedcalculation method to determine the driving amount, and decision meansfor determining calculation means, from among the first and secondcalculation means, that is suitable for vibration applied to thehousing.

[0028] In this image stabilization apparatus, the decision means maymake the determination by comparing the detection result of thedetection means with a predetermined reference value.

[0029] This image stabilization apparatus may further comprise anautomatic mode switching means for causing the driving means to operateby the driving amount determined by the calculation means that isdetermined from among the first and second calculation means by thedecision means.

[0030] In this image stabilization apparatus, when an angulardisplacement amount based on the information on angular displacementdeviates from a predetermined range a predetermined number of times ormore within a predetermined sampling time, the decision means may beadapted to determine that panning or tilting of the housing is occurringand select calculation means that is suitable for the panning or tiltingfrom among the first and second calculation means.

[0031] In this image stabilization apparatus, when the angular velocitydeviates from the predetermined range said number of times or more thansaid number of times within the predetermined sampling time, thedecision means may be adapted to determine that the user is on aconveyance so as to select calculation means that is suitable forvibration caused by the conveyance from among the first and secondcalculation means.

[0032] The image stabilizing apparatus according to the presentinvention may further comprise an observation optical system, and theinforming section may include a display provided within a field of viewof the observation optical system.

[0033] In the image stabilization apparatus according to the presentinvention, the informing section may include a sound generator withwhich the informing section provides information using a sound.

[0034] According to another aspect of the present invention, there isprovided a binocular comprising:

[0035] a pair of eyepiece optical systems;

[0036] a pair of objective optical systems;

[0037] an intermediate optical system provided on an optical axisbetween the eyepiece optical systems and objective optical systems;

[0038] a housing accommodating the eyepiece optical systems, theobjective optical systems and the intermediate optical system;

[0039] holding means for holding a part of optical members that composethe intermediate optical system in such a way as to allow angulardisplacement of said part of the optical members relative to thehousing, in order to maintain the position of said part of the opticalmembers in a predetermined state;

[0040] driving means for angularly displacing said part of the opticalmembers in the direction for restoring the position of said part of theoptical members that have been angularly displaced by the holdingmember;

[0041] control means for controlling a driving amount of the drivingmeans, the control means including detection means for detectinginformation on angular displacement of said part of the optical memberscaused by the holding means and determination means for determining,based on the information detected by the detection means, a mode forcontrolling the housing that is suitable for vibration applied to thehousing; and

[0042] an informing section that informs a user of the control methoddetermined by the determination means.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]FIG. 1 is a drawing schematically showing the internal structureof a binocular as an embodiment of the present invention.

[0044]FIG. 2A is a front view showing the structure of an imagestabilization apparatus 100 in the embodiment of the present invention.

[0045]FIG. 2B is a cross sectional view taken on line A-A in FIG. 2A.

[0046]FIG. 3 is a rear view of the binocular according to the firstembodiment of the present invention.

[0047]FIG. 4 is a top view of the binocular according to the firstembodiment of the present invention.

[0048]FIG. 5 is a front view of the binocular according to the firstembodiment of the present invention.

[0049]FIG. 6 is a block diagram showing the structure of the imagestabilization apparatus 100 in the binocular according to the firstembodiment of the present invention.

[0050]FIG. 7 is a top view showing the structure of a mode setting dial105 of the image stabilization apparatus 100 in the binocular accordingto the first embodiment of the present invention.

[0051]FIG. 8 is a flow chart showing a control process performed by aCPU 601 of the image stabilization apparatus 100 in the binocularaccording to the first embodiment of the present invention.

[0052]FIG. 9 is a top view showing the structure of a navigation displaychanging switch 107 of the image stabilization apparatus 100 in thebinocular according to the first embodiment of the present invention.

[0053]FIG. 10 is a drawing illustrating a display 201 within the fieldof view 200 of the binocular according to the first embodiment of thepresent invention.

[0054]FIG. 11 is a top view of a binocular according to the secondembodiment of the present invention.

[0055]FIG. 12 is a drawing illustrating displays 202, 203 and 204 withinthe field of view 200 of the binocular according to the secondembodiment of the present invention.

[0056]FIGS. 13A and 13B are diagrams for illustrating comparison ofreference values and signals in a process for determining vibrationreduction mode performed by the CPU 601 of the image stabilizationapparatus 100 according to the first embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] In the following, embodiments of the present invention will bedescribed. In the following embodiments, descriptions will be made withreference to an image stabilization apparatus equipped in a binocular.However, it should be understood that the present invention may also beapplied to other optical apparatus. For example, the invention may beapplied to a monocular apparatus such as a telescope etc.

[0058] First, a description will be made of a binocular equipped with animage stabilization apparatus as a first embodiment of the presentinvention.

[0059] Referring to FIG. 1 and FIG. 2A, The binocular equipped with animage stabilization apparatus according to the embodiment has abinocular optical system 10, a housing 1 accommodating the binocularoptical system, and an image stabilization apparatus 100. The imagestabilization apparatus 100 is adapted to detect vibration generatedduring use of the binocular, such as vibration applied to the housing 1due to hand shake, and to suppress such vibration.

[0060] As shown in FIG. 1, the binocular optical system 10 includes anobjective optical system 11, an eyepiece optical system 13, anintermediate optical system 12 disposed between the objective opticalsystem 11 and the eyepiece optical system 13. As illustrated in FIGS. 1and 3, the objective optical system 11 includes objective lenses 11R and11L. As shown in FIGS. 1, 4 and 5, the eyepiece optical system 13includes an eyepiece barrels 101R and 101L and eyepiece lenses 13R and13L. The intermediate optical system 12 functions to direct a light fluxfrom the objective optical system 11 to the eyepiece optical system 13.The intermediate optical system 12 is provided for performing, whenvibration occurs in the binocular, optical compensation to prevent anobject from disappearing out of the field of view. In this embodiment,the intermediate optical system 12 includes erecting prisms 12R and 12L.

[0061] The image stabilization apparatus 100 has a gimbal mechanism 110.The gimbal mechanism 110 includes an outer gimbaled member 111 having arotation axis parallel to X-axis and an inner gimbaled member 112 havinga rotation axis parallel to Y-axis. The inner gimbaled member 112 issupported by rotation shaft 112 a in such a way as to be rotatablerelative to the outer gimbaled member 111. The outer gimbaled member 111is supported by rotation shaft 111 a in such a way as to be rotatablerelative to the housing 1. The inner gimbaled member 112 holds theerecting prisms 12R and 12L between two plate members 112 b and 112 c.The plate members 112 b and 112 c have openings 112 d and 112 erespectively at the positions of the left and right optical paths. Withthe above-described structure, when vibration or panning/tilting of thehousing 1 occurs, the gimbaled members 111 and 112 are rotated relativeto the housing respectively by inertial force so that the direction ofthe optical axes of the erecting prisms 12R and 12L would be keptunchanged with respect to the inertial system (i.e. with respect to theearth).

[0062] On the outer gimbaled member 111, there is mounted an angularvelocity detector 121 for detecting the angular velocity ωx of therotational movement about the rotation axis 111 a parallel to X-axis. Onthe inner gimbaled member 112, there is mounted an angular velocitydetector 122 for detecting the angular velocity ωy of the rotationalmovement about the rotation axis 112 a parallel to X-axis. Each of theangular velocity detectors 121 and 122 may be composed, for example, ofa piezoelectric vibration gyro sensor.

[0063] In addition, an angular displacement detector 141 for detectingan angular displacement (i.e. a change in the angular position) θxcaused by the rotation is attached to the rotation shaft 111 a forrotation about the axis parallel to X-axis. Furthermore, an actuator 131for rotationally driving the rotation shaft 111 a that has beenrotationally displaced in the rotational direction for returning backthe rotation axis 111 a is also attached to the rotation shaft 111 a.Similarly, to the rotation axis 112 a for rotation about the axisparallel to Y-axis, there is attached an angular displacement detector142 for detecting an angular displacement θy caused by the rotation andan actuator 132 for rotationally driving the rotation shaft 112 a thathas been rotationally displaced in the rotational direction forreturning back the rotation axis 112 a. Thus, the angular displacementof the rotation of the outer and inner gimbaled members 111 and 112about axes parallel to X-axis and Y-axis can be detected based onoutputs of the angular displacement detectors 141 and 142. Thedirections of rotational drive by the actuators 131 and 132 are suchdirections with which the optical axis of the erecting prism 12R and 12Lmounted on the gimbaled member 111 and 112 that have been rotated byinertial force would be restored to the original position (i.e. theoptical axis of the objective optical system 11). Each of the actuators131 and 132 may include, for example, a servo mechanism. Each of theangular displacement detectors 141 and 142 may include a rotary encoder.

[0064] As shown in FIG. 4, the image stabilization apparatus 100 isfurther provided with a button 251 for turning on/off the vibrationreduction function disposed on the top surface of the housing 1, a soundgenerator 254 and a battery box 108. In addition, as shown in FIG. 5,the image stabilization apparatus 100 is provided with a switch 107 forswitching a navigation display disposed on the front surface of thehousing 1 and a mode setting dial 105. Furthermore, referring to FIG. 6,the image stabilization apparatus 100 has a CPU (central processingunit) 601, an amplifier section 602, an A/D converter 603, a referencevalue storing section 604, a D/A converter 605 and a calculator section606. The control system as described above is accommodated in theinterior of the housing 1. The image stabilization apparatus 100 isfurther provided with a display within the field of view 201 disposedwithin the field of view of either one of the eyepiece lenses 13R and13L. In addition, a display 109 and a focus knob 106 are also providedon the front side surface of the housing 1.

[0065] The mode setting dial 105 is a dial type switch used forselecting the vibration reduction mode of the image stabilizationapparatus 100. The apparatus according to this embodiment has twovibration reduction modes (mode VR1 and mode VR2) and an automatic modefor switching the mode VR1 and the mode VR2 automatically. While theapparatus according to this embodiment is described to have two modesVR1 and VR2 by way of example, the apparatus may be adapted to have morethan two modes to be switched. The mode VR1 is a mode that is suitablefor stabilizing the image at the occasion of performing observation on asteady ground or observation which involves frequent panning and tiltingoperations (e.g. at the time of bird watching). On the other hand, themode VR2 is a mode suitable for stabilizing the image at the occasion ofperforming observation on a swinging or wavering board of a conveyance(e.g. a ship, a vehicle, an airplane or a helicopter etc.). The modesetting dial 105 has five positions to be switched, that is, “POWER-OFF”position 1051, “POWER-ON (VR AUTO: auto vibration reduction)” position1052, “VR1” position 1053, “VR2” position 1054 and “SHIFT” position1055. When the mode setting dial 105 is set to the “POWER-OFF” position1051, power supply from the battery box 108 to each section of the imagestabilization apparatus 100 is turned off and disabled, so that thegimbal mechanism 110 is placed into a locked state in which the gimbalmechanism 110 is maintained at the position of the center of the opticalaxis without angular displacement. Under this state, the binocularbehaves as an ordinary binocular that is not provided with a vibrationreduction function. When the mode setting dial 105 is set to the“POWER-ON (VR AUTO)” position 1052, the image stabilization apparatus100 is turned on, and the vibration reduction mode is set to theautomatic switching mode. When the mode setting dial 105 is set to the“VR1” position 1053 or the “VR2” position 1054, the vibration reductionmode is set to the vibration reduction mode VR1 or VR2 respectively. Theoperation under the dial setting to the “SHIFT” position 1055 will bedescribed later.

[0066] In the following, functions characterizing the present inventionwill be specifically described. As shown in FIG. 10, the display withinthe field of view 201 is composed, for example, of an LED or otherelements, and it is disposed in the field of view 200 of either one ofthe eyepiece lenses 13R and 13L. Under the state in which a vibrationreduction mode is selected by setting of the mode setting dial 105 tothe “VR1” position 1053 or the “VR2” position, if it is determined,based on the level or degree of the external vibration actually appliedto the housing 1, that the selected mode is not the optimal mode, thedisplay in the field of view 201 indicates with red light. This promptsthe user to change the mode selected by the mode setting dial 105 toanother mode. Such a prompting function for changing the mode isreferred to in this embodiment as a vibration reduction mode navigationfunction.

[0067] Referring to FIG. 9, a navigation display changing switch 107 hasmultiple positions to be switched, namely, a “NAVI-OFF” position 901, aneye-mark position 902 and an ear-mark position 903. When the navigationdisplay changing switch 107 is set to the eye-mark position 902, theprompt for changing the vibration reduction mode is performed by meansof the display within the field of view 201. On the other hand, when thenavigation display changing switch 107 is set to the ear-mark position903, the indication by the display within the field of view 201 is notperformed, but prompt for changing the vibration reduction mode isperformed by beep sound or voice sound for prompting mode changegenerated by the sound generator 254. When the beep sound is used, itssound duration time or its frequency may be modulated in accordance withthe vibration reduction mode. When the navigation display changingswitch is set to the “NAVI OFF” position 901, the vibration reductionmode navigation function is disabled.

[0068] The vibration reduction on/off button 251 is enabled when themode setting dial 105 is set to either one of the “POWER-ON (VR AUTO)”position 1052, the “VR1” position 1053, the “VR2” position 1054 or the“SHIFT” position 1055. When the mode setting dial 105 is set to eitherone of the “POWER-ON (VR AUTO)” position 1052, the “VR1” position 1053or the “VR2” position 1054, the state in which the vibration reductionmode is disabled and the state in which the vibration reduction mode isenabled are alternately switched by manipulation of the vibrationreduction on/off button. Under the state in which the vibrationreduction mode is disabled, the gimbal mechanism 110 is placed in thelocked state in which the gimbal mechanism is positioned at the originalposition without angular displacement. Under the state in which thevibration reduction mode is enabled, the vibration reduction modecorresponding to the setting of the mode setting dial 105 (i.e. eitherone of the auto switching mode, the VR1 mode or the VR2 mode) isenabled. Therefore, during observation under the vibration reductionmode (i.e. either one of the auto switching mode, the VR1 mode or theVR2 mode), the vibration reduction on/off button is useful for the user,when the user wants to disable the vibration reduction mode to lock thegimbal mechanism instantaneously for power saving or other reasons.

[0069] On the other hand, when the mode setting dial 105 is set to the“SHIFT” position 1055, the vibration reduction mode is alternatelyswitched between VR1 and VR2 by manipulation of the vibration reductionon/off button 251. Therefore, during observation under the mode VR2, themode setting dial 105 may be set to the “SHIFT” position in preparationfor panning and tilting operation for following up an object such as abird or an airplane that may possibly comes within the field of view, sothat the vibration reduction mode can be changed to the mode VR2 bymanipulating (or pressing) the vibration reduction of/off button 251. Inconnection with this, when the mode setting dial 105 is set to the“SHIFT” position 1055, the automatic vibration reduction mode change andthe information by the display within the field of view 201 will not beenabled.

[0070] The above-described navigation function is so adapted to promptthe user to change the vibration reduction mode selected by the modesetting dial 105 into another mode. However, it may be modified toinform the user of the optimal mode determined by the external vibrationlevel actually applied to the housing 1. If the function is so modified,the user can know the optimal mode determined by the apparatus, andtherefore the user can be aware of the difference between the optimalmode and the mode selected by the user. In addition, if the modeselected by the user is also displayed together with the optimal modedetermined by the apparatus, the user can recognize the difference inthe modes easily.

[0071] Next, in the following, control operations by the CPU 601 of theimage stabilization apparatus will be described.

[0072] The CPU 601 reads a program stored in the reference value storingsection 604 upon turning-on of the power supply and executes the programto operate in the manner described in the flow chart presented in FIG.8. First, in step 801, the CPU 601 receives, via the A/D converter 603,signals Vωx and Vωy that have been obtained by amplifying angularvelocity ωx and ωy detected by the angular velocity detector 121 and 122by a predetermined gain in the amplifier section 602. In addition, theCPU 601 also receives via the A/D converter 603, signals Vθx and Vθythat have been obtained by amplifying angular displacement θx and θydetected by the angular velocity detector 141 and 142 by a predeterminedgain by the amplifier section 602.

[0073] Next in step 802, the CPU 601 compares the received angularvelocity signals Vωx and Vωy with reference angular velocity values ±Vc1stored in the reference value storing section 604 in advancerespectively. In addition, the CPU 601 compares the received angulardisplacement signals Vθx and Vθy with reference angular displacementvalues ±Vc2 stored in the reference value storing section 604 in advancerespectively. Based on the above-mentioned comparison, the CPU 601determines whether the optimal mode is the mode VR1 or the mode VR2.

[0074] In the apparatus according to this embodiment, the angularvelocity signals Vωx and Vωy are used as information for detectingvibration caused by conveyance. Specifically, as will be seen from FIG.13A, if at least one of the angular velocity signals Vωx and Vωy becomeslarger than ±Vc1 or smaller than −Vc1, it is determined that the user ison a conveyance and so the mode VR2 is appropriate. In addition, inorder not to mistakenly interpret angular velocity signals Vωx and Vωycorresponding to an user's unintentional action as those correspondingto vibration of a conveyance, a sampling time Ts is set in the apparatusaccording to this embodiment as shown in FIG. 13A. If the state in whichat least one of the angular velocity signals Vωx and Vωy becomes largerthan +Vc1 or smaller than −Vc1 occurs more than once during the samplingtime Ts, it is determined that the optimal mode is the mode VR2.

[0075] On the other hand, the angular displacement signals Vωx and Vωyare used as information for detecting panning and tilting operations.Specifically, as will be seen from FIG. 13B, if at least one of theangular displacement signals Vωx and Vωy becomes larger than +Vc2 orsmaller than −Vc2, it is determined that the user is performing apanning or tilting operation and so the mode VR1 is appropriate. As inthe case of the angular velocity signals, in order to prevent erroneousinterpretation of output corresponding to an user's unintentionalaction, if the state in which at least one of the angular displacementsignals Vθx and Vθy becomes larger than +Vc1 or smaller than −Vc2 occursmore than once during the sampling time Ts, it is determined that theoptimal mode is the mode VR1.

[0076] In the case in which the determination of the optimal modeconflicts between VR1 and VR2 (for example, when a user on a conveyanceis performing panning or tilting operation), in other words, in the casein which at least one of Vωx and Vωy becomes larger than +Vc1 or smallerthan −Vc1 more than once within the sampling time Ts and at least one ofVωx and Vωy becomes larger than +Vc2 or smaller than −Vc2 more than oncewithin the sampling time Ts, it is determined in the apparatus accordingto this embodiment that the mode VR1 for panning/tilting is the optimalmode.

[0077] The above-described criteria in step 802 are summarized asfollows:

[0078] (1) When during the sampling time Ts, both Vωx and Vωy are withinthe range larger than −Vc1 and smaller than +Vc1 (or deviate from thisrange only once) and at least one of Vθx and Vθy becomes smaller than−Vc2 or larger than +Vc2 more than once, it is determined that theoptimal mode is the mode VR1;

[0079] (2) When during the sampling time Ts, both Vωx and Vωy are withinthe range larger than −Vc1 and smaller than +Vc1 (or deviate from thisrange only once) and both Vθx and Vθy are within the range larger than−Vc2 and smaller than +Vc2 (or deviate from this range only once), it isdetermined that the optimal mode is the mode VR2;

[0080] (3) When during the sampling time Ts, at least one of Vωx and Vωybecomes smaller than −Vc1 or larger than +Vc1 more than once and atleast one of V θx and Vθy becomes smaller than −Vc2 or larger than +Vc2more than once, it is determined that the optimal mode is the mode VR1;and

[0081] (4) When during the sampling time Ts, at least one of Vωx and Vωybecomes smaller than −Vc1 or larger than +Vc1 more than once and bothVωx and Vωy are within the range larger than −Vc2 and smaller than +Vc2(or deviate from this range only once), it is determined that theoptimal mode is the mode VR2 As per the above, in step 802, it ispossible to determine the vibration reduction mode VR1 or VR2 that isoptimal to the vibration level applied to the binocular, by comparingthe angular velocity signals Vωx and Vωy and angular displacementsignals Vθx and Vθy with the reference values ±Vc1 and ±Vc2respectively.

[0082] Next in step 803, the CPU 601 reads to which position 1052 to1055 the mode setting dial 105 is set. When the mode setting dial 105 isset to the “POWER-ON (VR AUTO)” position 1052, which means thatautomatic switching of the vibration reduction mode is selected, theprocess proceeds to step 804. In step 804, the CPU 601 controls tocreate outputs for causing the actuators 131 and 132 to rotationallydrive the rotation shafts 111 a and 111 b of the gimbal mechanism 110 inaccordance with the optimal vibration mode VR1 or VR2 determined in step802.

[0083] Specifically, in step 804, if the vibration mode determined instep 802 is the mode VR1, the CPU 601 controls to amplify the angularvelocity signals Vωx and Vωy at a predetermined gain α1 and to amplifythe angular displacement signals Vθx and Vθy at a predetermined gain β1and to output them. The output signals α1×Vωx, α1×Vωy, β1×Vθx and β1×Vθyare converted by the D/A converter 605 into analog signals and theninput to the calculation section 606. The calculation section 606performs predetermined calculation processing such as addition orintegration on the output α1×Vωx and the output β1×Vθx and outputs theresults to the actuator 131 for rotationally driving the rotation shaft111 a about X-axis. Thus, the actuator 131 rotationally drives therotation shaft 111 a with a driving voltage reflecting the outputs ofthe angular velocity signal Vωx and the angular displacement signal Vθxso as to rotate the outer gimbaled member 111 in the direction forbringing the optical axis of the erecting prism 12R and 12L closer tothe original position (i.e. the optical axis of the objective opticalsystem 11). In addition, the calculation section 606 also performscalculation processing such as addition or integration on the outputα1×Vωy and the output β1×Vθy and outputs the results to the actuator 132for rotationally driving the rotation shaft 112 a about Y-axis. Thus,the actuator 132 rotationally drives the rotation shaft 112 a with adriving voltage reflecting the outputs of the angular velocity signalVωy and the angular displacement signal Vθy so as to rotate the innergimbaled member 112 in the direction for bringing the optical axis ofthe erecting prism 12R and 12L closer to the original position (i.e. theoptical axis of the objective optical system 11).

[0084] On the other hand, in the case in which the vibration reductionmode determined in step 802 is VR2, the CPU 601 also controls in step804 to amplify the angular velocity signals Vωx and Vωy and the angulardisplacement signals Vθx and Vθy so as to output them, but theamplification is performed at gains α2 and β2 respectively. While gainsα1 and β1 are predetermined values for realizing the vibration mode VR1that is suitable for panning and tilting operations, gains α2 and β2 arepredetermined values for realizing the vibration reduction mode VR2 thatis suitable for the vibration of a conveyance. The gains α1 and β1 inthe mode VR1 are set in such a way that the gimbal mechanism 110 isrestrained to the original position more strongly than in the mode VR2.In other words, the gains α1 and β1 for the mode VR1 are so set that thefield of view follows the movement of the housing upon panning andtilting operations. On the other hand, the gains α2 and β2 in the modeVR2 are set in such a way that the restraint of the gimbal mechanism 110to the original position is weaker than in the mode VR1. In other words,the gains α2 and β2 in the mode VR2 are so set that the field of view iskept as constant (or steady) as possible relative to the inertial system(i.e. relative to the earth) even if the binocular vibrates due tovibration of a conveyance. Specifically, the ratio of the gain α1 forthe angular velocity signal to the gain β1 for the angular displacementsignal in the mode VR1 is made larger than the ratio of the gain α2 forthe angular velocity signal to the gain β2 for the angular displacementsignal in the mode VR2.

[0085] As per the above, the automatic switching of the vibrationreduction mode between VR1 and VR2 is realized in step 804.

[0086] On the other hand, when it is turned out in step 803 that themode setting dial 105 is set to the “VR1” position 1053 or the “VR2”position 1054, the process proceeds to step 805. In step 805, it isfurther determined whether the mode setting dial 105 is in the “VR1”position 1053 or in the “VR2” position 1054. When it is determined thatthe mode setting dial 105 is in the “VR1” position 1053, the processproceeds to step 806. In step 806, it is determined whether or not theoptimal vibration reduction mode determined in step 802 is identical tothe mode VR1 set by the mode setting dial 105. If they are notidentical, the process proceeds to step 807, in which information forprompting mode change is presented to the user, since the currently setvibration reduction mode is not appropriate. The way of informing theuser is pursuant to the setting by the navigation information changingswitch 107. Specifically, when the eye-mark position 902 is selected,the LED in the display within the field of view 201 is turned on in red,while when the ear-mark position 903 is selected, a beep sound or avoice sound is generated from the sound generator 254, and then theprocess proceeds to step 808. In connection with this, when thenavigation information changing switch 107 is set to the “NAVI OFF”position 901, the information is not presented and the process proceedsto step 808.

[0087] In the process shown in the flow chart of FIG. 8, it isdetermined in step 806 whether or not the optimal vibration reductionmode determined in step 802 is identical to the mode set by the user,which is determined in step 805. However, as described before, in thepresent invention the process may be modified in such a way as to informthe user of the optimal vibration reduction mode determined in step 802.In that case, step 806 for determining whether or not the optimalvibration reduction mode determined in step 802 is identical to the modeset by the user is not necessary (i.e. can be omitted). Therefore, theinformation made in step 807 will be information on the optimalvibration reduction mode determined in step 802.

[0088] In step 808, in order to realize the mode VR1, the CPU 601controls to amplify the angular velocity signals Vωx and Vωy at apredetermined gain α1 and to amplify the angular displacement signalsVθx and Vθy at a predetermined gain β1 and to output them in like manneras in step 804. Thus, the actuators 131 and 132 rotationally drive therotation shafts 111 a and 112 a respectively with driving voltagesreflecting the outputs of the angular velocity signals and the angulardisplacement signals so as to realize the vibration reduction mode VR1.

[0089] In step 808, the vibration reduction mode is switched to theoptimal vibration reduction mode determined in step 802 automatically.However, in the present invention, whether or not the mode suggested bythe information in step 807 is to be selected may be left to user'sdiscretion. In that case, step 808 is not necessary (i.e. can beomitted). Therefore, if the user considers that observation under themode selected by himself or herself is satisfactory, the user cancontinue the observation while maintaining the current mode withoutfollowing the information. In addition, even if the user considers thatobservation under the current mode selected by himself or herself issatisfactory, the user can change the mode once when a mode differentfrom the currently selected mode is suggested by the information and ifthe suggested mode provides better observation, the user would observewith the suggested mode. If the user finds, after changing the mode tothe suggested mode, that observation under the mode selected by himselfor herself is more preferable for him or her than observation under thesuggested mode, the user would change the mode from the suggested modeto the mode previously selected by the user again.

[0090] As per the above, the present invention can provide an apparatusthat reflects user's intention or taste to a greater degree.

[0091] After the above-described steps, the process proceeds to step812, in which the CPU 601 detects whether or not the vibration reductionon/off button 251 has been manipulated within a predetermined time. Whenit is detected that the vibration reduction of/off button has beenmanipulated, the process proceeds to step 813, in which the CPU 601outputs a signal for commanding the actuators 131 and 132 to return therotation shafts 111 a and 112 a to the original positions and tomaintain (or lock) them at that state. That signal is sent to theactuators 131 and 132 via the D/A converter 605, the calculation section606, and the actuators 131 and 132 return the rotation shafts 111 a and112 a to their original positions to maintain (or lock) them in thatstate. Thus, the gimbal mechanism 110 of the image stabilizationapparatus 100 will not rotate from the original position, and thereforethe binocular behaves as an ordinary binocular that does not have avibration reduction function. The locking of the rotation shafts 111 aand 112 a is maintained until it is detected that the vibrationreduction on/off button 251 is manipulated (or pressed) again. If it isdetermined in step 814 that the vibration reduction on/off button 251 ispressed again and the locking is released, or if it is determined instep 812 that the vibration reduction on/off button 251 has not beenmanipulated, the process returns to step 801.

[0092] Referring back to step 805, if it is determined in step 805 thatthe mode setting dial 105 is in the “VR2” position 1054, the processproceeds to step 809. In step 809, it is determined whether or not theoptimal vibration reduction mode determined in step 802 is identical tothe mode VR2 set by the mode setting dial 105. If they are notidentical, the process proceeds to step 810, in which information forprompting mode change is presented to the user in like manner as in step807, since the currently set vibration reduction mode is notappropriate.

[0093] As described before, the process may be modified in such a way asto inform the user of the optimal vibration reduction mode that isdetermined in step 802. In that case, step 809 for determining whetheror not the optimal vibration reduction mode determined in step 802 isidentical to the mode set by the user determined in step 805 is notnecessary (i.e. can be omitted). Therefore, step 809 and step 810 arenot necessary, and information of the optimal vibration reduction modedetermined in step 802 is made only in step 807.

[0094] Then the process proceeds to step 811. In step 811, in order torealize the mode VR2, the CPU 601 controls to amplify the angularvelocity signals Vωx and Vωy at a predetermined gain α2 and to amplifythe angular displacement signals Vθx and Vθy at a predetermined gain β2and to output them in like manner as in step 804. Thus, the actuators131 and 132 rotationally drive the rotation shafts 111 a and 112 arespectively with driving voltages reflecting the outputs of the angularvelocity signals and the angular displacement signals so as to realizethe vibration reduction mode VR2. After that, the process proceeds tostep 812.

[0095] As described before, whether or not the mode suggested by theinformation in step 810 is to be selected may be left to user'sdiscretion. In that case, step 810 is not necessary (i.e. can beomitted).

[0096] Referring back to step 803, if the mode setting dial 105 is setto the “SHIFT” position 1055, the process proceeds to step 815. In step815, it is determined whether the vibration reduction on/off button 251has been manipulated (or pressed) within a predetermined time. In thestate in which the mode setting dial 105 is set to the “SHIFT” position,the vibration reduction mode is switched between VR1 and VR2automatically. Therefore, if it is determined in step 815 that thevibration reduction on/off button 251 has not been pressed, the processproceeds to step 816, and in order to realize the vibration reductionmode same as the previously set mode, which is assumed here to be themode VR1 for example, if the mode set in the latest step 816 is VR1, theCPU 601 controls to amplify the angular velocity signals Vωx and Vωy ata predetermined gain α1 and to amplify the angular displacement signalsVθx and Vθy at a predetermined, gain β1 and to output them. On the otherhand, if it is determined in step 815 that the vibration reductionon/off button 251 has been pressed, the process proceeds to step 816,and in order to realize the vibration reduction mode different from thepreviously set mode (i.e. in order to realize the mode VR2, if the modeset in the latest step 816 is VR1,), the CPU 601 controls to amplify theangular velocity signals Vωx and Vωy at a predetermined gain α2 and toamplify the angular displacement signals Vθx and Vθy at a predeterminedgain β2 and to output them. Thus, the actuators 131 and 132 rotationallydrive the rotation shafts 111 a and 112 a so as to realize vibrationreduction mode VR1 or VR2.

[0097] As per the above, in the binocular having the image stabilizationapparatus 100 according to this embodiment, it is possible to realize amode with which vibration reduction mode is automatically switched inaccordance with the level or degree of vibration of the binocular. Underthis automatic mode, it is possible, by setting a sampling time Ts, todistinguish movement of the binocular caused unintentionally by the userfrom intentional panning/tilting operations or vibration caused byconveyance. In addition, even if there is a time lag between detectionof the angular velocity of the gimbal mechanism and detection of theangular displacement of the gimbal mechanism, it is possible todetermine the optimal vibration reduction mode.

[0098] In addition, when a vibration reduction mode is set by a user athis or her will, the apparatus can inform the user whether that mode isthe optimal vibration reduction mode or not, based on theabove-described determination of the optimal vibration reduction mode,to prompt the user to change the vibration reduction mode to the optimalmode. In this way, the user can notice whether or not the vibrationreduction mode selected by him or her is appropriate, and eveninexperienced user can appropriately select the mode. Therefore, it ispossible to bring out the performance of the image stabilizationapparatus fully.

[0099] In the apparatus according to the above-described embodiment, theoptimal vibration reduction mode is determined based on whether theangular velocity signal or the angular displacement signal deviates froma reference range more than once within the sampling time Ts. However,the frequency criterion is not limited to “more than once”, but it mayalso be “more than twice” or other desirable frequency.

[0100] In steps 804, 808, 811 and 816 in FIG. 8, the gains are varied inaccordance with the vibration reduction mode in order to realize modesVR1 and Vr2. But the apparatus may be modified in such a way that themodes VR1 and VR2 are realized not only by varying the gains but byperforming calculation or other processing that is predetermined foreach mode.

[0101] Next, as a second embodiment, an apparatus in which amodification is made to the displayed mark that appears, in accordancewith the informing process of steps 807 and 810, in the display 201within the field of view 200 in the apparatus according to the firstembodiment is modified.

[0102] In the second embodiment, as shown in FIG. 12, a display withinthe field of view 200 includes a display 203 indicating an upward redtriangle mark, a display 204 indicating a downward red triangle mark anda display 202 disposed between these displays indicating a greencircular mark. These displays can be realized by LEDs or other devices.On the upper surface of a housing 1 of the binocular, as shown in FIG.11, there is provided vibration reduction mode changing buttons 104 aand 104 b having the shapes corresponding to the shapes of the marks ofthe displays 203 and 204. The button 104 a is to be operated uponchanging the vibration reduction mode to mode VR2 when the currently setmode is mode VR1, while the button 104 b is to be operated upon changingthe vibration reduction mode to mode VR1 when the currently set mode ismode VR2.

[0103] When in step 807 (in the process shown in the flow chart of FIG.8) the currently set mode VR1 is not the optimal mode, the CPU 601causes the upward triangle mark of the display within the field of view203 to be turned on in red. If the user presses the changing button 104a of the same shape in response to the turned-on mark, the CPU 601causes the circular mark of the display within the field of view 202 tobe turned on in green, and the process proceeds to step 811, in whichthe process for the vibration reduction mode VR2 (that is the mode setafter the mode change) is performed. On the other hand, if the user doesnot press the changing button 104 a of the same shape in step 807, theprocess proceeds to step 808, in which the process for the vibrationreduction mode VR1 is continued without a mode change. Similarly, whenin step 810 the currently set mode VR2 is not the optimal mode, the CPU601 causes the downward triangle mark of the display within the field ofview 204 to be turned on in red. If the user presses the changing button104 b of the same shape in response to the turned-on mark, the CPU 601causes the circular mark of the display within the field of view 202 tobe turned on in green, and the process proceeds to step 808, in whichthe process for the vibration reduction mode VR1 (that is the mode setafter the mode change) is performed. On the other hand, if the user doesnot press the changing button 104 b of the same shape in step 810, theprocess proceeds to step 811, in which the process for the vibrationreduction mode VR2 is continued without a mode change.

[0104] The binocular provided with the image stabilization apparatusaccording to the second embodiment having the above-described structurerealizes an advantageous effect that the user can change the vibrationreduction mode to select the optimal mode by operating the button 104 aor 104 b by a finger in accordance with a figure indicated in thedisplay within the field of view during observation without detachingthe eyes from the eyepiece lenses 13R and 13L.

[0105] In the process of providing information on the optimal modedetermined in step 802, the information may be provided by visualdisplays or sounds specific to the respective modes that are differentfrom each other. It is preferable that the mode selected by user beindicated in the field of view to inform the user of the mode. When boththe mode selected by the user and the optimal mode determined in step802 are displayed, the user can conveniently recognize the differencebetween those modes at sight.

[0106] The displays within the field of view 203 and 204 may be composedof LEDs or other elements that can emit a color light selected from morethan two color lights. In that case, the comparison of the angularvelocity signal and the angular displacement signal with the referenceranges may be arranged in such a way that the degrees of deviations ofthose signals from the respective reference ranges are classified intotwo or more levels. Thus, in the process of informing the user in steps807 and 810, those levels (or degrees) of the deviation are representedby corresponding colors of light. For example, when the degree of thedeviation is relatively low, the displays within the field of view 203and 204 are caused to emit yellow light, while when the degree of thedeviation is relatively high, the displays 203 and 204 are caused toemit red light. Thus, the user can make a decision on the vibrationreduction mode in a customized way in accordance with his or herintention, for example, in such a way as to change the vibrationreduction mode only when the degree of the deviation is high. Therefore,it is possible to enlarge the variety of use for user of the binocular.

[0107] The apparatus according to the above-described embodiment has twovibration reduction modes (VR1, VR2), but the present invention is alsoapplicable to more than two vibration reduction modes (VR1, VR2, VR3, .. . , VRn).

[0108] The apparatus according to the above-described embodiment isprovided with a gimbaled member on which prisms are mounted, angularvelocity feedback control means and position feedback control means forcontrolling the position of the gimbaled member. However, the presentinvention is also applicable to other types of optical elements.

[0109] For example, the present invention can be applied to an apparatusthat uses a variable-angle prism for vibration reduction, which iscomposed of two glass plates and liquid having a high refractive indexincluded between the glass plates in a sealed manner. (Thevariable-angle prism itself has been already known, and described forexample in Japanese Patent Application Laid-Open Nos. 10-319325 and2000-10143.) In that case, the present invention can be applied to anapparatus that has a variable-angle prism position detector that detectsan inclination angle of one of the glass plates and a driving devicesuch as a motor for driving that glass plate in a direction forcorrecting an inclination of the optical system based on the detectionresult.

[0110] The present invention can be applied to various apparatus inwhich an inclination of the optical axis of an observation opticalsystem having an erecting prism or other element is detected and theinclination is corrected based on a detection result.

[0111] The apparatus according to the present invention may be providedwith a mode selecting switch with which a user can select automatic modeswitching and manual mode switching that allows the user to selectdesired mode. In this case, the user can select a desired mode at his orher will depending on circumstances and the user's operation skill.

[0112] As per the above, the present invention can provide an imagestabilization apparatus having a good usability.

What is claimed is:
 1. An image stabilization apparatus comprising: ahousing accommodating an optical system in the interior thereof; holdingmeans for holding a part of optical members that compose said opticalsystem in such a way as to allow angular displacement of said part ofthe optical members relative to said housing, in order to maintain theposition of said part of the optical members in a predetermined state;driving means for angularly displacing said part of the optical membersin the direction for restoring the position of said part of the opticalmembers that have been angularly displaced by said holding member;control means for controlling a driving amount of said driving means,said control means including detection means for detecting informationon angular displacement of said part of the optical members caused bysaid holding means and determination means for determining, based on theinformation detected by said detection means, a mode for controllingsaid housing that is suitable for vibration applied to said housing; andan informing section that informs a user of said control methoddetermined by said determination means.
 2. An image stabilizationapparatus according to claim 1, wherein said angular displacementinformation comprises information on angular velocity of said holdingmeans and/or information on angular displacement amount of said holdingmeans.
 3. An image stabilization apparatus according to claim 1, whereinthe determination by said determination means is made based on acomparison of a predetermined reference value and said angulardisplacement information.
 4. An image stabilization apparatus accordingto claim 3, wherein said reference value comprises a reference value forthe angular velocity and/or a reference value for the angulardisplacement amount.
 5. An image stabilization apparatus according toclaim 3, wherein determination by said determination means is made basedon a comparison of said reference value and said angular displacementinformation obtained within a predetermined sampling time, and based onthe number of times said angular displacement information becomes largerthan and/or smaller than said reference value.
 6. An image stabilizationapparatus according to claim 1, wherein the control mode determined bysaid determination means is selected for at least two vibrationreduction modes.
 7. An image stabilization apparatus according to claim1, wherein the apparatus is so adapted that the user can select anautomatic switching mode in which the control mode is automaticallyswitched to the mode determined by said determination means based on theangular displacement information detected by said detection means or auser setting mode in which the user is allowed to select the controlmode.
 8. An image stabilization apparatus according to claim 1, whereinsaid informing section provides information on the control modedetermined by said determination means.
 9. An image stabilizationapparatus according to claim 7, wherein when the selected mode is saiduser setting mode, said informing section provides information onwhether the mode selected under said user setting mode and the modedetermined by said determination means are different or identical. 10.An image stabilization apparatus according to claim 1, wherein theapparatus is so adapted that the user can select and set any mode basedon the control mode of which the user is informed by said informingsection.
 11. An image stabilization apparatus according to claim 10,further comprising an observation optical system, wherein said informingsection includes a display section disposed within a view field of saidobservation optical system; the apparatus is provided with a modeselecting section for changing over the mode, the mode selecting sectionincluding a button for selecting any one of said modes and said displaysection displaying a mark which has a same shape as that of said button.12. An image stabilization apparatus according to claim 1 furthercomprising first calculation means for performing calculation on adetection result of said detection means based on a first predeterminedcalculation method to determine said driving amount, second calculationmeans for performing calculation on a detection result of said detectionmeans based on a second predetermined calculation method to determinesaid driving amount, and decision means for determining calculationmeans, from among said first and second calculation means, that issuitable for vibration applied to said housing.
 13. An imagestabilization apparatus according to claim 12, wherein said decisionmeans makes said determination by comparing the detection result of saiddetection means with a predetermined reference value.
 14. An imagestabilization apparatus according to claim 12 further comprising anautomatic mode switching means for causing said driving means to operateby said driving amount determined by the calculation means that isdetermined from among said first and second calculation means by saiddecision means.
 15. An image stabilization apparatus according to claim12, wherein when a displacement amount based on said information onangular displacement deviates from a predetermined range a predeterminednumber of times or more within a predetermined sampling time, saiddecision means determines that panning or tilting of said housing isoccurring and selects calculation means that is suitable for the panningor tilting from among said first and second calculation means.
 16. Animage stabilization apparatus according to claim 12, wherein when saidangular velocity deviates from said predetermined range said number oftimes or more than said number of times within said predeterminedsampling time, said decision means determines that the user is on aconveyance so as to select calculation means that is suitable forvibration caused by said conveyance from among said first and secondcalculation means.
 17. An image stabilizing apparatus according to claim1 further comprising an observation optical system, wherein saidinforming section includes a display provided within a field of view ofsaid observation optical system.
 18. An image stabilization apparatusaccording to claim 1, wherein said informing section includes a soundgenerator with which said informing section provides information using asound.
 19. A binocular comprising: a pair of eyepiece optical systems; apair of objective optical systems; an intermediate optical systemprovided on an optical axis between said eyepiece optical systems andobjective optical systems; a housing accommodating said eyepiece opticalsystems, said objective optical systems and said intermediate opticalsystem; holding means for holding a part of optical members that composesaid intermediate optical system in such a way as to allow angulardisplacement of said part of the optical members relative to saidhousing, in order to maintain the position of said part of the opticalmembers in a predetermined state; driving means for angularly displacingsaid part of the optical members in the direction for restoring theposition of said part of the optical members that have been angularlydisplaced by said holding member; control means for controlling adriving amount of said driving means, said control means includingdetection means for detecting information on angular displacement ofsaid part of the optical members caused by said holding means anddetermination means for determining, based on the information detectedby said detection means, a mode for controlling said housing that issuitable for vibration applied to said housing; and an informing sectionthat informs a user of said control method determined by saiddetermination means.